<?php

$arr = $array = array(
    array(
        'element1' => a,
        'element2' => b
    ),
    array(
        'element1' => c,
        'element2' => d
    )
);

print_r(array_map("getFunc", $arr));

function getFunc($a) 
{ 
    return $a['element1']; 
}

?>

Array
(
    [0] => a
    [1] => c
)